calculability—the other by their incalculability. The one set, when at work, are not easily put wrong, while the other set are characterized by great delicacy of construction. An Animal is a delicately-constructed Machine. 221. But perhaps the reader may object to our use of the rifle as an illustration. For although it is undoubtedly a delicately-constructed machine, yet a rifle does not represent the same surpassing delicacy as that, for instance, which characterizes an egg balanced on its longer axis. Even if at full cock, and with a hair trigger, we may be perfectly certain it will not go off of its own accord. Although its object is to produce a sudden and violent transmutation of energy, yet this requires to be preceded by the application of an amount of energy, however small, to the trigger, and if this be not spent upon the rifle, it will not go off. There is, no doubt, delicacy of construction, but this has not risen to the height of incalculability, and it is only when in the hands of the sportsman that it becomes a machine upon the condition of which we cannot calculate. Now, in making this remark, we define the position of the sportsman himself in the Universe of Energy. The rifle is delicately constructed, but not surpassingly so; but sportsman and rifle, together, form a machine of surpassing delicacy, ergo the sportsman himself is such a machine. We thus begin to perceive that a human being, or indeed an animal of any kind, is in truth a machine of a delicacy that is practically infinite, the condition or motions of which we are utterly unable to predict. In truth, is there not a transparent absurdity in the very thought that a man may become able to calculate his own movements, or even those of his fellow ? Life is like the Commander of an Army. 222. Let us now introduce another analogy-let us suppose that a war is being carried on by a vast army, at the head of which there is a very great commander. Now, this commander knows too well to expose his pcrson; in truth, he is never seen by any of his subordinates. He remains at work in a well-guarded room, from which telegraphic wires lead to the headquarters of the various divisions. He can thus, by means of these wires, transmit his orders to the generals of these divisions, and `by the same means receive back information as to the condition of each. Thus his headquarters become a centre, into which all information is poured, and out of which all commands are issued. Now, that mysterious thing called life, about the nature of which we know so little, is probably not unlike such a commander. Life is not a bully, who swaggers out into the open universe, upsetting the laws of energy in all directions, but rather a consummate strategist, who, M sitting in his secret chamber, before his wires, directs the movements of a great army. 223. Let us next suppose that our imaginary army is in rapid march, and let us try to find out the cause of this movement. We find that, in the first place, orders to march have been issued to the troops under them by the commanders of each regiment. In the next place, we learn that staff officers, attached to the generals of the various divisions, have conveyed these orders to the regimental commanders; and, finally, we learn that the order to march has been telegraphed from headquarters to these various generals. Descending now to ourselves, it is probably somewhere in the mysterious and well-guarded brain-chamber that the delicate directive touch is given which determines our movements. This chamber forms, as it were, the headquarters of the general in command, who is so well withdrawn as to be absolutely invisible to all his subordinates. 224. Joule, Carpenter, and Mayer were at an early period aware of the restrictions under which animals are placed by the laws of energy, and in virtue of which the power of an animal, as far as energy is concerned, is not creative, but only directive. It was seen that, in order See an article on "The Position of Life," by the author of this work, in conjunction with Mr. J. N. Lockyer, "Macmillan's Magazine," September, 1868; also a lecture on "The Recent Developments of Cosmical Physics," by the author of this work. to do work, an animal must be fed; and, even at a still earlier period, Count Rumford remarked that a ton of hay will be administered more economically by feeding a horse with it, and then getting work out of the horse, than by burning it as fuel in an engine. 225. In this chapter, the same line of thought has been carried out a little further. We have seen that life is associated with delicately-constructed machines, so that whenever a transmutation of energy is brought about by a living being, could we trace the event back, we should find that the physical antecedent was probably a much less transmutation, while again the antecedent of this would probably be found still less, and so on, as far as we could trace it. 226. But with all this, we do not pretend to have discovered the true nature of life itself, or even the true nature of its relation to the material universe. What we have ventured is the assertion that, as far as we can judge, life is always associated with machinery of a certain kind, in virtue of which an extremely delicate directive touch is ultimately magnified into a very considerable transmutation of energy. Indeed, we can hardly imagine the freedom of motion implied in life to exist apart from machinery possessed of very great delicacy of construction. In fine, we have not succeeded in solving the problem as to the true nature of life, but have only driven the difficulty into a borderland of thick darkness, into which the light of knowledge has not yet been able to penetrate. Organized Tissues are subject to Decay. 227. We have thus learned two things, for, in the first place, we have learned that life is associated with delicacy of construction, and in the next (Art. 220), that delicacy of construction implies an unstable arrangement of natural forces. We have now to remark that the particular force which is thus used by living beings is chemical affinity. Our bodies are, in truth, examples of an unstable arrangement of chemical forces, and the materials which composed them, if not liable to sudden explosion, like fulminating powder, are yet pre-eminently the subjects of decay. 228. Now, this is more than a more general statement; it is a truth that admits of degrees, and in virtue of which those parts of our bodies which have, during life, the noblest and most delicate office to perform, are the very first to perish when life is extinct. "Oh! o'er the eye death most exerts his might, So speaks the poet, and we have here an aspect of things in which the lament of the poet becomes the true interpretation of nature. |